The present invention is directed to an apparatus for supplying gas through the wall of a metallurgical container. More specifically, the present invention is directed to such an apparatus usable for supplying a gas to a molten metal within a metallurgical container for treatment of such metal.
In a known such apparatus, a gas permeable fireproof refractory brick is positioned within the wall of the metallurgical container, and gas is caused to pass through such porous brick, and into the molten metal within the container. However, in this known arrangement, the open pores of the brick result in a unique source of premature wear of the brick. Such wear is caused particularly by molten metal entering the pores of the porous brick.
An additional arrangement is known whereby a fireproof refractory brick is covered by a metal cover, for example of sheet metal, and the brick has a very high number of closed pores, whereby the gas substantially cannot be caused to flow through the brick itself. As a result, the gas essentially flows through the area between the metal cover and the brick. A ring-shaped gas discharge cross section thus is formed, and this cross section creates a very uneven gas discharge flow into the molten metal because of the relatively uneven surface conditions of the brick and the metal cover. In other words, the metal cover does not fit evenly around the brick. As a result, at some spots around the brick no gas at all or very little gas is discharged, with the result that the treatment of the molten metal is not satisfactory.
Both of the above known arrangements have the disadvantage of rapid closing up of the cross section of the gas discharge areas, thereby hampering considerable the gas supply operation. Thus, in the first arrangement, the molten metal enters the pores of the porous brick. In the second known arrangement, the molten metal passes into the small dimensioned areas between the metal cover and the brick.